diagonal: [16] Diagonal is commonly used simply as a synonym for oblique, but in strict mathematical terms it denotes a line joining two non-adjacent angles of a polygon. This reveals far more clearly its origins. It comes from diagōnālis, a Latin adjective derived from Greek diagónios. This was a compound formed from the prefix dia- ‘across’ and gōníā ‘angle’ (as in English polygon), meaning ‘from angle to angle’. Gōníā is related ultimately to English knee and genuine. => genuine, knee, polygon
diagonal (adj.)
1540s (implied in diagonally), from Middle French diagonal, from Latin diagonalis, from diagonus "slanting line," from Greek diagonios "from angle to angle," from dia- "across" (see dia-) + gonia "angle" (see -gon). As a noun, from 1570s.
实用例句
1. The book has a diagonal black stripe on the cover.
书的封面上有条连接对角的黑斜线.
来自《简明英汉词典》
2. Footsteps had scored a diagonal path through the snow.
脚印在雪地上留下了一条对角线.
来自《简明英汉词典》
3. Draw a diagonal line to divide the square into two triangles.